Keep in mind that Bill was talking about programming in assembly language for extremely resource-constrained systems there. Even today, if you're trying to writ

Keep in mind that Bill was talking about programming in assembly language for extremely resource-constrained systems there. Even today, if you're trying to write an extremely small/fast program/inner loop in assembly, you had better be relying on "dangerous assumptions" like that, or else the result is going to be worse than what a compiler could do.